4.5 The Poison Sky

Written by Helen Raynor
Directed by Dougles Mackinnon
Produced by Susie Liggat
Executive Producers:

• Russell T Davies
• Julie Gardner
• Phil Collinson

Length: 45 minutes

As the Sontarans choke the Earth, the Doctor battles to keep both Martha and Donna alive, but the TARDIS is transported to the Sontaran ship with Donna on board, and General Skorr clones Martha. Luke Rattingham fails miserably to convince his students that they will have a new beginning. UNIT and the Sontarans begin the war, but 10% of the gas is unidentified, and the Sontarans need it for something else.

Air Date: 03/05/08
Viewers (millions): 6.53

Cast:

• David Tennant (the Doctor)
• Catherine Tate (Donna Noble)
• Freema Agyeman (Martha Jones)

Guest Stars:

• Billie Piper (Rose Tyler)
• Christopher Ryan (General Staal)
• Rupert Holliday (Evans Colonel Mace)
• Bridget Hodgson (Captain Price)
• Dan Starkey (Commander Skorr)
• Bernard Cribbins (Wilfred Mott)
• Jacqueline King (Sylvia Noble)
• Ryan Sampson (Luke Rattigan)
• Christian Cooke (Ross Jenkins)
• Clive Standen (Private Harris)
• Wesley Theobald (Private Gray)
• Meryl Fernandes (Female Student)
• Leeshon Alexander (Male Student)
• Kirsty Wark (Herself)
• Lachele Carl (US Newsreader)
• Jack Steed (Lieutenant Skree)

Next Episode: The Doctor's Daughter

Previous Episode: The Sontaran Stratagem